From a legality point of view there is no need to descend , as per the provision of MEL , as long as speed brakes ares operative. Airmanship might dictate otherwise depending on the situation , this is where captain decision comes into play and that's why robots haven't replaced pilots yet.
Similar question just to give food for thought . AC ESS BUS FAULT leads to the deactivation of cabin oxygen masks door ( Auto+manual are inop) and this is not even indicated in ECAM , just a little note on FCOM saying so. So now your pax don't have oxygen in case of depressuraziation.
Would you descent to FL250 ? Considering that your A320 has become an "ATR" , would you continue at FL390 because there is no "if scenarios" ?
Would you ask you your purser to use the Manual Release Tool to open manually all oxygen masks doors in the cabin scaring your pax , or would you stay quite and proceed to your destination?